In a message dated 1/25/99 7:50:34 AM Pacific Standard Time, [log in to unmask] writes: << As you all know. We are getting into doing a basic BGA assembly. The new question which came up is, since we run a water soluble flux paste. How are we going to know if it is clean under the BGA?? Any suggestions beside going to a no clean paste?? Thanks in advance. John >> Mornin' John... Ionograph is one way...won't catch everything, but it'll tell ya' if you got flux residues on your board...but then again, it doesn't really pin point if it's from beneath the BGA. SIR testing is another, but that takes a while though. If you wanna get a "warm n fuzzy" that your cleaner is capable of doing the job. One thing you can do is what I was taught when selecting a cleaner to buy, is get yourself some glass plates (heat resistant tempered glass to be sure!) and make yourself up some glass slugs, or chips if you will, that are the same size as the largest BGA you think you'll do. Glue them to the glass plate at different stand-off heights and squirt some colored flux beneath the slugs. Send it through a reflow oven to bake it some, and then it's bathtime! Then just take a gander at what the plate looks like after it comes out of your cleaner. That'll show you without a doubt, what your cleaner is capable of. -Steve Gregory- ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################